Method and apparatus for making an undergarment having overlapping or butt-type side seams

ABSTRACT

A method for forming an undergarment comprises the steps of transporting a two-dimensional web in a substantially flattened position on a transport device, cutting the web along a transverse edge to form a two-dimensional pre-form, gripping the pre-form adjacent each waist section with a gripping device in four gripping areas, jointly rotating at least the gripping means which hold the gripping areas in the region of the first transverse edge of the pre-form around a first axis of rotation extending substantially parallel to the transverse edges of the pre-form, rotating each gripping device around a respective axis of rotation extending generally parallel to the longitudinal sides of the pre-form to place the sealing areas located along the same longitudinal side in a contacting relationship, joining the superimposed sealing areas in a sealing unit, and releasing the undergarment from the gripping device. The apparatus comprises an umbrella-type mechanism.

FIELD OF THE INVENTION

The invention relates to a method of making an undergarment having sideseams from a substantially two-dimensional web, the web having twolongitudinal sides and a first transverse edge extending transversely tothe longitudinal sides.

BACKGROUND OF THE INVENTION

From EP-A-0 187 728 (Heran) a disposable absorbent article is knownhaving manually tearable side seams. The seams may be butt-type seams oroverlapping side seams.

WO 93/09742 describes an absorbent article having overlappingultrasonically-bonded side seams.

It is an object of the present invention to provide a method forproducing an undergarment, in particular an absorbent article, havingstrong side seams, wherein the sealing areas can be accuratelypositioned in a sealing configuration in a reproducible manner.

It is another object of the present invention to provide a method forproducing an undergarment, in particular a disposable absorbent article,having side seams which can be easily manually separated.

It is a further object of the invention to provide a method forproducing an undergarment having aesthetically looking side seams whileproducing little trim and operating at high speeds.

It is another object of the invention to provide a method for producingan undergarment having an elasticized waist providing accurate processcontrol and small variability in the placement of the side seams.

It is a further method to provide an apparatus for carrying out theabove method, which apparatus is of relatively simple construction, andallows high-speed formation of the side seams.

SUMMARY OF THE INVENTION

The method according to the invention comprises the steps of:

transporting the web in a substantially flattened position on atransport means along a transport trajectory,

cutting the web along a second transverse edge to form a two-dimensionalpre-form, the pre-form comprising the first and the second transverseedge of the web and two longitudinal edges, each longitudinal edgehaving two waist sections and a crotch section located intermediate thewaist sections, a sealing area being located adjacent and inboard ofeach waist section,

gripping the pre-form adjacent each waist section with gripping means infour gripping areas, the gripping areas being located near each sealingarea,

jointly rotating at least the gripping means which hold the grippingareas in the region of the first transverse edge around a first axis ofrotation extending substantially parallel to the transverse edges of thepre-form to place the first transverse edge generally parallel andopposite to the second transverse edge,

superimposing the sealing areas which are located along the samelongitudinal side in a contacting relationship,

joining the superimposed sealing areas in a sealing means, thus formingthe absorbent article, and

releasing the absorbent article from the gripping means.

The method according to the invention doubles over the pre-form alongits transverse center line and accurately places the sealing areas ofthe pre-form in a superimposed relationship. The method involves acontrolled handover of the pre-form from the transport means to afolding-and-sealing unit, wherein the position of each sealing areaduring all phases of the transport step and the handover step is dearlydefined. This allows for high speed formation of the undergarment's sideseams with little process variability. This is especially important incase the transverse edges of the pre-form are elasticated and thereforeneed to be confined to a stretched state in all phases of the transport-and sealing process.

The seams that are formed can be butt-type seams, which are made bysuperimposing the sealing areas in the region of the first waistsections with their interior sides onto the interior sides of thesealing areas in the region of the second waist sections. For thebutt-type side seams, the sealing areas in the region of each waistsection are located on the same side of the pre-form.

In a preferred embodiment of the method according to the invention, thestep of superimposing the sealing areas comprises rotating each grippingmeans around a respective axis of rotation extending generally parallelto the longitudinal sides of the pre-form to place the sealing areaswhich are located along the same longitudinal side in an overlappingrelationship, to form overlapping side seams. In the overlapping sideseams the sealing areas in the region of the first waist section arelocated on a different side of the pre-form than the sealing areas inthe region of the second waist sections.

By consecutively rotating the ears of the absorbent articleperpendicularly to the plane of the pre-form, the sealing areas are madeto overlap and can be contacted for instance by an ultrasonic sealingunit to attach the overlapping sealing areas. Overlapping side seams arelocated in the plane of the side panels of the finished undergarment.Hence the seams are of pleasing aesthetics and are wearer-friendly.Furthermore, in case the undergarment is formed by a disposableabsorbent article, the overlapping side seams have a high shear strengthbut can easily be manually detached for disposal of the absorbentarticle. The overlapping seams may alternatively be connected bymechanical fasteners, such as Velcro® hook-type and loop-type materialsor by means of adhesive tapes. Such re-fastenable seams can be undone bythe user without ripping the article and can be reclosed for furtheruse.

The longitudinal sides of the pre-form are preferably parallel to thelength-direction of the web, such that each preform has the same widthas the width of the web. Alternatively, the longitudinal sides of thepreforms are formed by the transverse side of the web, such that thepreforms are transported with their longitudinal sides perpendicular tothe direction of transport.

The web from which the absorbent article is formed comprises a flexiblematerial, which may be a woven fabric, a non-woven material, athermoplastic film or any combination or laminate thereof. Theundergarment formed by the method according to the invention can bere-usable and may be used in combination with disposable absorbentinserts. Such inserts may comprise a liquid-pervious topsheet, aliquid-impervious backsheet and an absorbent core interposedtherebetween.

An embodiment of the method according to the invention comprises thesteps of forming the web by combining a liquid-impervious backsheet, anabsorbent core and a liquid-pervious topsheet, such that the finishedundergarment after formation of the side seams is a disposable absorbentarticle of the pull-on type. Disposable absorbent articles of thepull-on type are characterized by having pre-formed side seams insteadof the usual mechanical or adhesive tape fasteners.

The web from which the undergarment is formed may be of elastic orelasticated material, such that the web is elastically extensible. Ifthe web is of substantially non-elastic material, the method accordingto the invention comprises a length compensating step. In thelength-compensating step, at least the first axis of rotation isdisplaced to prevent stretching the pre-form in the direction of thelongitudinal edge, when the pre-form is doubled-over along itstransverse center line.

When overlapping side seams are formed, a width-compensating step in thedirection of the transverse edge may be carried out. In this step, thedistance between the gripping areas located in the region of the sametransverse edge is decreased. This prevents stretching of the pre-formin the direction of the transverse edges when the gripping means arerotated around their gripper axes.

The need for length or width compensation of the pre-form, depends onthe way the pre-from is folded. If the pre-form is folded around an axiswhich is located on the concave side of the fold, a length-compensationstep is required. If the pre-form is folded around an axis which islocated on the convex side of the fold, the pre-form material isgathered by the folding and no length compensation is necessary.

In an embodiment of the method according to the invention, the grippingmeans, after gripping the article, are rotated around a main axis whichextends generally transversely to the longitudinal sides of the webtowards a stationary or rotating sealing unit. In this embodiment thegripping means are rotated towards and away from the transporttrajectory of the web. In this way a number of gripping means can beplaced onto the main axis and can consecutively be rotated towards andaway from the transport means carrying the web, such that high speedsealing of the pre-forms is effected.

Preferably the gripping means are rotated tangentially to the transporttrajectory at a velocity which is substantially equal to the speed oftransport of the web along the transport trajectory. Hereby the relativevelocity between the gripping means and the web is made substantiallyzero such that handover from the transport means onto the gripping meanscan take place at a continuous speed of transport of the web.

An apparatus for carrying out the method according to the inventioncomprises at least one folding-and-sealing unit, whichfolding-and-sealing unit has:

a first and second carrier arm, each carrier arm being hingingly mountedon a hinging axis, the hinging axes extending generally transversely tothe carrier arms,

gripping means attached to each carrier arm for gripping the absorbentarticle in four gripping areas,

carrier arm-actuating means for rotating at least one carrier arm aroundits hinging axis to a sealing position and

sealing means for contacting the article in the sealing areas when thecarrier arms and gripping means are in the sealing position.

In a preferred embodiment, each carrier arm is in one point attached toa connecting arm. Each connecting arm is in on one end attached to ahinge point that is comprised in a lower member which is displaceablerelative to the hinging axes of the carrier arms, along a center line.The center line is located midway between the hinging axes and extendsgenerally transversely or perpendicular to the hinging axes. In thismanner an "umbrella type" construction is formed. This construction isrelatively simple and accurately operates at high speeds. By varying thedistance between the hinging axes on which the carrier arms aresuspended and the hinging points of the connecting arms, the opposedcarrier arms are moved outwardly and inwardly respectively. Theumbrella-type mechanism allows accurate alignment of the sealing areasin a simple and reproducible manner.

Each gripping means may be rotatable around a respective gripper axiswhich is positioned generally parallel to the carrier arms, theapparatus comprising gripper actuating means for rotating each grippingmeans around the gripper axes to a sealing position. By rotation of thegripping means around the gripper axes, overlapping side seams areproduced. The actuating means for rotation of the grippers may be formedby a contacting element which engages with the gripping means uponrotation of the carrier arms and which guides the grippers to rotatearound their gripper axes, or by other actuators, such as cans, springsor wires.

In a further embodiment of the apparatus according to the invention,each carrier arm is connected with its hinging axis to a first end of arespective pivot member, the second end of each pivot member beingrotatably connected to a central pivot axis located on the center lineand extending generally parallel to the hinging axes. By rotation of thepivot members around the centered pivot axis a length-compensation takesplace which prevents deformation of non-elastically extensible webs.

Another embodiment of an apparatus according to the invention comprisestwo distance-control arms, each distance-control arm being with one endhingingly connected to a respective connecting arm and being withanother end hingingly connected to a respective hinge point in theregion of a center line.

The distance control arms in cooperation with the connecting arms imparta unique position to each gripping means throughout the whole grippingand sealing cycle, for each position of the connecting arms.

In a preferred embodiment, the gripping means are formed by vacuumgrippers, comprising a perforated surface across which a pressuredifferential is maintained. Such grippers can easily engage in anon-damaging manner with the web and can quickly be disengaged byswitching off the vacuum and by venting the grippers.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the method and apparatus in accordance with the inventionwill be described in detail with reference to the accompanying drawings.In the drawings:

FIGS. 1 and 2 show embodiments of an undergarment having overlapping andbutt-type side seams respectively,

FIG. 3 shows a top plan view of a two-dimensional pre-form for formingan absorbent article having side seams,

FIG. 4 shows a cross-sectional view of the article of FIG. 3 along lineI--I.

FIG. 5 shows a schematic side elevational view of a folding-and-sealingunit according to the invention in the gripping position,

FIG. 6 shows a top elevational view of the apparatus of FIG. 5,

FIGS. 7 and 8 show a side elevational view of the apparatus of FIG. 5 inthe sealing position,

FIG. 9 shows a schematic front elevational view of the apparatus asshown in FIG. 8,

FIG. 10 shows a schematic side elevational view of an embodiment of theapparatus according to the invention in an alternative sealing position,

FIG. 11 shows a schematic side elevational view of an embodiment of anumbrella-type apparatus for forming side seams,

FIG. 12 shows a cross-sectional view of an umbrella-type apparatus forforming side seams in the gripping position,

FIG. 13 shows a cross-sectional view of an umbrella-type apparatus forforming side seams in the sealing position,

FIGS. 14-17 show schematic side elevational views of the gripping andsealing phases of an umbrella-type apparatus,

FIG. 18 shows a top cross-sectional view of the umbrella-type apparatusof FIGS. 12 and 13,

FIGS. 19-23 show cross-sectional views of different embodiment oftwo-dimensional pre-forms for forming undergarments having side seams,

FIGS. 24 and 25 show a schematic top plan view of a web from which thepre-forms are cut in a length-wise and in a cross-wise directionrespectively,

FIG. 26 shows a schematic top view of the gripping and sealing means onformation of a butt-type side seam,

FIG. 27 shows a schematic top view of the gripping and sealing means onformation of a combined overlapping and butt-type side seam, and

FIG. 28 shows a schematic top view of the gripping and sealing means onformation of a three-layer overlapping side seam.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a finished undergarment 1, in particular a disposableabsorbent article of the pull-on type having a front panel 3 and a backpanel 5. The front panel and the back panel are joined together at thearea of overlapping side seams 7, 9 to form a three dimensionaldisposable garment having leg openings 11, 13 and a waist opening 15.The side seams 7,9 are formed by overlapping parts of the front panel 3and the back panel 5. Overlapping side seams have favorablecharacteristics with respect to shear strength (in the plane of thefront and back panels) and can, in case the undergarment is a disposableabsorbent article, be easily torn apart for removal of a used articlefrom the wearer.

Alternatively, the overlapping side seams may be joined by Velcro-typeside seams comprising patches of hook-type and loop-type material. Thesepatches may be located parallel to the sides seams 7,9 or may be locatedperpendicular to the seams 7,9. Alternatively, the side seams may bejoined by adhesive tape taps extending perpendicularly to the seams 7,9.The Velcro®-type sealing means or adhesive tape sealing means areattached by the manufacturer to form the three dimensional garment.After the garment has been attached on a wearer, the seams 7,9 can beunfastened for inspection of the inside of the article and can afterinspection be re-closed by the user for further use.

The waist opening 15 and the leg openings 11,13 are elasticated so thatthey contract and snugly fit around the waist and legs of the wearer toprovide gasketing seals which prevent liquids of leaking from thegarment 1.

FIG. 2 shows an undergarment 1 having outwardly located butt-type seams16, 18. The butt-type seams 16, 18 are made by folding the pre-form, orblank, from which the article 1 is formed along its transverse centerline 19 and superimposing the sealing areas that are located on the samesurface of the blank in a face-to-face relationship. The seams may beformed by pressure bonding, ultrasonic bonding, heat sealing adhesiveattachment, or mechanical attachment.

The sealing line 14 of the butt-type seam is preferably located inboardfrom the outer periphery and leaves the outer edges of the seamunattached in order to maintain a soft edge.

The butt-type side seams 16 and 18 may be located on the inside of theundergarment 1. Inner seams can be obtained when the pre-form, or blank,of the undergarment is folded along its transverse center line 19 sothat its inner surface if facing outwardly upon formation of the seams.Subsequently, by an inverting step, the seams 16 and 18 are turnedinwardly.

The undergarment 1 as shown in FIGS. 1 and 2 can comprise a single layeror multiple layers of woven or non-woven material, and may comprise athermoplastic film. The undergarment may form a re-usable diaper holderwhich is to be used in combination with a disposable absorbent insertcore. Preferably, the undergarment forms a unitary disposable absorbentarticle, in which a liquid-impermeable backsheet, an absorbent core anda liquid permeable topsheet are combined to form an integral structure.

As used herein, the term "absorbent article" refers to devices whichabsorb and contain body exudates, and, more specifically, refers todevices which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term "disposable" is used herein to describe absorbentarticles which are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner). A"unitary" absorbent article refers to absorbent articles which areformed of separate parts united together to form a coordinated entity sothat they do not require separate manipulative parts like a separateholder and liner. The present invention is also applicable to otherabsorbent articles such as incontinent briefs, incontinentundergarments, diaper holders and liners, feminine hygiene garments, andthe like.

FIG. 3 shows the pre-form 17, which will be further referred to as"blank" 17, for forming an absorbent article having side seams. FIG. 4show a cross-sectional view of the blank 17 along the line I--I of FIG.3. The blank 17 comprises a liquid-pervious topsheet 21, aliquid-impervious backsheet 23 and an absorbent core 25 interposedbetween the topsheet and the backsheet. The blank 17 comprises twolongitudinal edges 27,29 and two transverse edges 31,33. Thelongitudinal edges 27,29 and the transverse edges 31,33 form theperiphery of the blank 17. The longitudinal edges 27,29 extend generallyin the direction of the longitudinal center line 20 and comprise cut-outregions which are to form the leg openings 11,13 of the absorbentarticle in its assembled state. The blank 17 comprises waist elastics35,37 and leg elastics 36,38. Each longitudinal edge 27,29 comprises afirst waist section 39,39' and a second waist section 41,41'. The waistsections 39,39' and 41,41' of the longitudinal edges 27,29 are locatedon both sides of a central crotch section 40,40' of each edge 27,29.Each waist section comprises a sealing area 43,45,47,49. A gripping area51,53, 55,57 is located adjacent each sealing area 43,45,47,49.

FIG. 5 shows a schematic side elevational view of the apparatus forforming an absorbent article having side seams according to theinvention. FIG. 6 shows a top elevational view of the apparatus of FIG.5. A continuous web 58 is transported in a substantially flattened statealong a transport trajectory on a conveyor belt 73 in a direction oftransport T. A cutting means 42 cuts the web transversely across itswidth to from individual blanks 17. The blanks 17 are transported intheir substantially flattened state on the conveyor belt 73, which isair-permeable and runs over a suction box 44. By suction, the blanks 17are held in a defined position on the conveyor belt, and the elasticelements 35,36,37,38 in the blanks 17 are prevented from contracting andfrom gathering the blanks.

As is shown in FIGS. 5 and 6, a folding-and-sealing unit 59 is locatedoverhead of the conveyor belt 73 and comprises gripping means 60,61,62and 63. In FIG. 5 only gripping means 61 and 63 are visible. Thegripping means are brought in contact with the liquid imperviousbacksheet 23 of the blanks 17 at the four gripping areas 51,53,55 and57. The gripping means 60-63 are rotatably mounted on carrier arms64,65,66 and 67. The carrier arms 64-67 are connected to a frame 72 andcan each be rotated around at least one hinging axis 75,77. The hingingaxes 75,77 extend perpendicular to the plane of the drawing in FIG. 5,and generally perpendicular to the carrier arms 64-67.

As shown in FIG. 6, two sealing means 78,79 are located on each side ofthe conveyor belt 73 and can be moved in a direction transversely to thedirection of transport T to contact an anvil carrier 69. The sealingmeans 78,79 may comprise heated elements which contact the anvil carrierunder pressures of between 1 and 10⁵ psi. Because the anvil carrier 69is simultaneously contacted by the sealing means 78,79 from both sidesand is squeezed between the sealing means, high pressures can be exertedon the side seams without the need for a heavy and rigid suspension ofthe anvil carrier 69.

The carrier arms 64-67 can be rotated upwardly around the hinging axes77,75 to a position in which they extend substantially perpendicular tothe conveyor belt 73, and such that the sealing areas 43-49 are broughtin proximity of the anvil carrier 69. This is illustrated in FIG. 7. Theactuating means for rotating the carrier arms 64-69 around the hingeaxes 75,77 may for instance be formed by levers or gears or any otherknown means.

As schematically indicated in FIG. 5, the carrierarm-actuating means forrotating the carrier arms around the hinging axes 75 and 77 may comprisea number of gears 74. The gears 74 for instance engage with acomplementary toothed surface on suspension arm 70. By moving the frame72 along the arm 70 towards the anvil carrier 69, the carrier arms 64-67are rotated upwardly. The direction of rotation of the carrier arms64-67 can in this embodiment be easily varied by selecting an even oruneven number of gears in the actuating means. Prior to, or duringrotation of the carrier arms, the frame 72 and the anvil carrier 69 mayin combination be lifted away from the conveyor belt 73 in the directionof the arrow F towards a sealing position.

In the embodiment FIGS. 5, 6 and 7, the blank 17 is stretched uponrotation of the carrier arms 64-67 around the hinging axes 75, 77.Stretching of the blank can be prevented by hinging the carrier arms64-67 around hinging axes which lie in the plane of the blank 17. Forhinging axes that are not located in the plane of the blank 17 but abovethe plane of the blank 17, a length compensation is required. Tocounteract the increase in length of the blank 17 caused by rotating thecarrier arms 64-67 upwardly, the folding-and-sealing unit 59 compriseslength-compensating means, which may for instance comprise a telescopicarrangement for varying the length of the carrier arms 64-67. In apreferred embodiment, the length-compensating means comprises asuspension of at least one of the hinging axes 75, 77 which causes avarying distance between the hinging axes 75,77 upon rotation of thecarrier arms. This is shown in the preferred folding-and-sealing unit 59of FIGS. 12 and 13.

As illustrated in FIG. 8, the sealing areas 45,47 and 43,49,respectively, are placed in an overlapping relationship by rotation ofeach gripping means 60-63 around a gripper axis 56,56', 68,68' whichextend generally parallel to the carrier arms 64-67. The superimposedsealing areas 45,47 and 43,49 are contacted between the anvil carrier 69and the sealing means 78,79, which may comprise an ultrasonic conductor.The ultrasonic energy imparted to the sealing areas puts thethermoplastic material of the sealing areas in a heat-softened state,such that upon compression of the sealing areas between the anvil andthe conductors an overlapping side seam is formed.

Instead of an overlapping seam, in which the sealing areas 43,49 aresuperimposed generally parallel to the plane of the anvil carrier 69,the gripping means 61,63 may be simultaneously rotated around theirgripper axis 56,56'; 68,68' in such a way that the sealing areas 43,49mutually abutt and extend generally perpendicular to the plane of theanvil carrier 69. Sealing can then occur for instance by compressing theabutting sealing areas 43, 49 in a direction generally parallel to thedirection of transport T by sealing means traveling withfolding-and-sealing unit 59 at matched speed. Different embodiments ofoverlapping and abutting side seams are shown in FIGS. 26 to 28.

FIG. 9 shows a frontal view of the sealing unit 59 in the sealingposition, prior to contacting the ultrasonic conductors 78,79 with theanvil carrier 69. The blank 17 has been indicated by a dashed line. Asupon rotation of the gripping means 61,62 around the gripper axes 56,56'the blank 17 is stretched, the mutual distance between the grippingmeans 61,62 is decreased upon rotation, for instance by displacing thegripping means along the hinging axis 75.

FIG. 10 shows a schematic side elevational view of a sealing unit,wherein the frame 72 is moved upwards in the direction of the arrow F,and wherein the carrier arms 64-67 are rotated downwardly after grippingthe blank 17. In this case the folding of the blank 17 causes an excessof material of the blank 17 to be comprised between the gripping means61 and 63. To maintain the blank 17 in a tensioned state, the carrierarms 65 and 67 may be moved outwardly along a transverse arm 71. To fixthe blank 17 in place during folding, the center point of the blank 17may be gripped by a gripping means 76 which may comprise for instance avacuum suction device.

FIG. 11 shows a side elevational view of a preferred embodiment of afolding-and-sealing unit 59 for forming side seams at high speed. Thecarrier arms 64-67 are mounted on the frame 72 which forms an uppermember. The frame 72 is mounted on the arm 70, which is rotated around amain axis 80 generally parallel to the hinging axes (75,77) in thedirection of the arrow R. The speed of rotation of the arm 70 around themain axis 80 is matched to the speed of transport of the blanks 17, andis such that the circumferential speed of the gripping means 60-63equals the speed of transport. The leading edge 24 of a blank 17 isgripped by the gripping means 61,62 at a moment when the relativevelocity between the blank 17 and the gripping means 61,62 is aboutzero. The geometry of the folding-and-sealing unit 59 is adapted to thelength of the blank 17, and is such that gripping means 60,63 contactthe trailing edge 26 of the blank 17 at the moment when the grippingmeans 60,63 are tangential to the conveyor belt 73.

The carrier-arm actuating means in the embodiment of FIG. 11 comprises alower member 84 and for each carrier arm a connecting arm 86, 88. Theconnecting arms 86,88 are connected in hinge points 89,90 to the carrierarms 64-67 and are hingingly connected to the lower member 84. The lowermember 84 is slidably mounted on the arm 70 such that the distancebetween the frame 72 and the lower member 84 can be varied. The carrierarms 64-67 are moved towards the anvil carrier 69, as indicated by thedashed lines, by moving the lower member 84 towards the main axis 80,while keeping the frame 72 stationary with respect to the arm 70.Evidently, it is also possible to move the carrier arms 64-67 to theirsealing position by moving the frame 72 along the arm 70 away from astationary lower member 84. The anvil carrier 69 is mounted on the arm70 and is rotated together with the carrier arms 64-67.

FIGS. 12 and 13 show detailed cross-sectional views of thefolding-and-sealing unit 59 in the gripping phase and in the sealingphase respectively, including the length-compensating means. The lengthcompensating means comprises two pivot arms 93,94 to which the carrierarms 64-67 are connected. The pivot arms 93,94 rotate around a centralaxis 103, which is connected to the arm 70. By rotation of the pivotarms 93,94 around axis 103, the distance between the hinging axes 75,77, which extend perpendicular to the plane of the drawing of FIGS. 12an 13, is varied upon rotation of the carrier arms 64-67.

Furthermore, distance control arms 96, 98 are provided, which are on oneside connected to the arm 70 and which have their opposite side attachedto the connecting arms 86,88. The distance control arms 96-98 couple thecarrier arms 64-67 with the lower member 84 in such a manner that foreach position of the lower member 84 along the arm 70, a single positionof the carrier arms 65, 67 corresponds.

FIG. 13 shows the lower member 84 in its retracted position wherein theconnecting arms 88, 86 have been pulled downwardly generally along thearm 70. The position of the connecting arms 88,86, the distance controlarms 96,98 and the pivot members 93,94 is uniquely determined for eachposition of the carrier arms 65,67. When the connecting arms 86,88 arepulled downwards by the lower member 84, the carrier arms 64-67 arerotated around the hinging axes 75,77, while the hinging axes are movedalong a circle segment which is centered on central axis 103.

FIGS. 14-17 schematically show how from a continuous web 58, individualblanks 17 are cut and how the sealing steps of the sides of the blanksare effected in the preferred embodiment of a folding-and-sealing unit59 in accordance with the invention. The web 58 is transported alongtransport means comprising guide rollers 105, 107,108 towards a pick-updrum 112 which is rotated in the direction of the arrow R'. The leadingedge 24 of the web 58 is sucked against a vacuum chamber 115 on theperiphery of the drum 112, whereas the trailing edge, which in theembodiment of FIG. 14 is formed after cutting of the web in a cuttingunit 110, is sucked onto the surface of drum 112 by vacuum chamber 116.

In the embodiment of FIG. 15 the web 58 is first placed across vacuumchambers 115 and 116, and is subsequently cut by cutting unit 110.Placing the cutting unit 110 tangential to the surface of the pick-updrum 112 allows for accurate control of the position of the trailingedge of each blank on the surface of the drum 112.

As shown in FIGS. 14 and 15 the gripping means 60, 61, 62 and 63 rotateon a circular track 118 which is tangential to the pick-up drum 112. Theleading edge 24 of the pre-form 17 that is held on the drum 112 betweenthe vacuum chamber 114 and 115, is gripped by the gripping means 61 and62. Subsequently, as shown in FIG. 16, the trailing edge of the blank isgripped by gripping means 60 and 63 from the vacuum chamber 115.

In the embodiment of FIGS. 14-17, the arm 70 of the folding-and-sealingunit 59 comprises an internal telescopic section, having an internal endcomprising a cam follower 85 that is to engage a stationary cam surface120. As shown in FIG. 17, the telescopic section 83 is pressed radiallyoutwardly towards circular track 119 such that the frame 72 is radiallydisplaced and the carrier arms are rotated towards the sealing position.

Inside the telescopic section 83, there may be included a furthertelescopic element which is to engage a further stationary cam surface,such that after the carrier arms have reached the sealing position, thiselement is pushed radially outwardly beyond the frame 72 to eject thefinished sealed article from the folding-and-sealing unit 59. Thisconstruction has not been shown in the figures.

In the embodiment of FIGS. 14-17, a further set of carrier arms islocated at each position 121, 122. A single, stationary sealing means 79such as an ultrasonic conductor is provided along which each set ofcarrier arms is rotated. For reasons of clarity only a single set ofcarrier arms has been shown in the FIGS. 14-16. As many as up to 30identical sets of arms may be located around the main axis 80 to allowsufficient time for the sealing operation while maintaining a high speedof transport of the web 58, which may for instance be transported atspeeds of 2 m/s or higher.

In an alternative embodiment, a sealing means 79 is provided for eachfolding-and-sealing unit at each position 121,122, and rotates with thefolding-and-sealing units around the main axis 80. This allows, at agiven speed of rotation around the axis 80, for sufficient time ofinteraction between the sealing means 79 and the material of thepre-form 17. Especially when the sealing means 79 are formed byheat-sealing means, it is important that sufficient time for heating upand cooling down of the side seam material is allowed. In an exampleraryembodiment, the heat sealing means 79 require about 700 ms sealing time,which may correspond to a rotation of the sealing means 79 around theaxis 80 of about 180 degrees.

FIG. 18 shows a top cross sectional view of the folding-and-sealing unit59, to more clearly depict the width-compensating means. Each carrierarm 64,65,66 and 67 is connected to a grooved member 124, 125, 126 and127. Each carrier arm 64-67 is mounted in a sleeve 128, 129 which ispart of the pivot members 93,94. The following description is given withrespect to gripping means 61, but equally applies to the other grippingmeans 60, 62 and 63. A grooved member 125 is mounted in a bracket 130,which is connected to the central axis 103 to be jointly rotated withthe pivot member 93. The bracket 130 carries an axis 132 generallyparallel to the hinging axes (75,77) on which a pin 134 is located whichfalls in a groove 131 of the member 125. Upon downward rotation of thecarrier arm 65 around the hinging axis 75, the grooved member 125 isaxially displaced along the axis 132, such that the distance between thegripping means 61 and 62 is decreased.

The gripping means 60-63 are preferably formed by vacuum gripping means.Each vacuum gripping means comprises a hollow body having a plurality ofoutlets on a gripping surface to contact the gripping areas of theblank. Each hollow body of the gripping members is connected via aflexible vacuum lead to a switched vacuum supply. This has not beenindicated in the figures.

As shown in FIGS. 12 and 13, the gripper actuating means for rotation ofthe gripping means 60-63 around the gripper axes 56,56', 68,68',comprises a protrusion 146,148 on each gripping means and an engagingsurface 150,152 mounted on the arm 70. When the carrier arms 64-67 arerotated to the sealing position in which they lie adjacent the arm 70,the protrusions 146,148 are guided along the engaging surfaces 150,152such that the gripping means are forced to rotate around the gripperaxes 56,56', 68,68'.

The FIGS. 19-23 show cross-sectional views of different blanks 17, alonga cross-section which extends parallel to the transverse sides of theblanks 17 and which cuts through two sealing areas 140, 142. FIG. 19shows an embodiment wherein the blank 17 from which the undergarment 1is formed comprises a topsheet 21, a backsheet 23, 23' and a core 25interposed between the topsheet and backsheet. The backsheet is formedby a thermoplastic film 23 and a non-woven outer layer 23'. Thethermoplastic film 23 is not coterminous with the non-woven outer layer23' such that in each side seam only two layers of the non-wovenmaterial 23' are present. Breathability of the absorbent structure isachieved through the regions of the non-woven material which are notcovered by the impermeable film 23.

In the embodiment of FIG. 20, the blank 17 comprises a thermoplasticfilm backsheet 23 having panels 135, 137 of stretchable materialattached there-to. Furthermore, there may be provided elasticatedstand-up cuffs 136,138 on each side of the core 21.

In the embodiment of FIG. 21, the blank 17 is intended to form anundergarment in the form of a re-usable holder for absorbent insertcores, and comprises a non-woven backsheet 23 and two pocket-formingflaps 143,144 in which the disposable insert core can be inserted andwhich serve to hold the insert core in the proper position with respectto the garment.

FIG. 22 shows a blank which is made a laminate of two non-woven layers23,23' or of a nonwoven layer 23' and a thermoplastic layer, both layersextending into the sealing areas 140,142 for improved strength of theseams.

FIG. 23 shows a blank wherein both the topsheet 21 and the backsheet 23extend into the sealing areas 140, 142 to form reinforced side seams.

While the topsheet 21, the backsheet 23, and the absorbent core 25 maybe assembled in a variety of well known configurations, preferredcon-figurations are described generally in U.S. Pat. No. 3,860,003entitled "Contractable Side Portions for Disposable Diaper" which issuedto Kenneth B. Buell on Jan. 14, 1975; and U.S. Pat. No. 5,151,092entitled "Absorbent Article With Dynamic Elastic Waist Feature Having APredisposed Resilient Flexural Hinge" which issued to Kenneth B. Buellet al. on Sep. 29, 1992; each of which is incorporated herein byreference.

The absorbent core 25 may be any absorbent means which is generallycompressible, conformable, non-irritating to the wearer's skin, andcapable of absorbing and retaining liquids such as urine and othercertain body exudates. The absorbent core 25 may be manufactured in awide variety of sizes and shapes (e.g., rectangular, hourglass,"T"-shaped, asymmetric, etc.) and from a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; meltblown polymers including coform;chemically stiffened, modified or cross-linked cellulosic fibers; tissueincluding tissue wraps and tissue laminates; absorbent foams; absorbentsponges; superabsorbent polymers; absorbent gelling materials; or anyequivalent material or combinations of materials. The configuration andconstruction of the absorbent core may also be varied (e.g., theabsorbent core may have varying caliper zones, a hydrophilic gradient, asuperabsorbent gradient, or lower average density and lower averagebasis weight acquisition zones; or may comprise one or more layers orstructures). The total absorbent capacity of the absorbent core 25should, however, be compatible with the design loading and the intendeduse of the absorbent article. Further, the size and absorbent capacityof the absorbent core 25 may be varied to accommodate wearers rangingfrom infants through adults. Exemplary absorbent structures for use asthe absorbent core 25 are described in U.S. Pat. No. 4,610,678 entitled"High-Density Absorbent Structures" issued to Weisman et al. on Sep. 9,1986; U.S. Pat. No. 4,673,402 entitled "Absorbent Articles WithDual-Layered Cores" issued to Weisman et al. on Jun. 16, 1987; U.S. Pat.No. 4,888,231 entitled "Absorbent Core Having A Dusting Layer" issued toAngstadt on Dec. 19, 1989; and U.S. Pat. No. 4,834,735, entitled "HighDensity Absorbent Members Having Lower Density and Lower Basis WeightAcquisition Zones", issued to Alemany et al. on May 30, 1989. Each ofthese patents are incorporated herein by reference.

The backsheet 23,23' is positioned adjacent the garment surface of theabsorbent core 25 and is preferably joined thereto by attachment means(not shown) such as those well known in the art. For example, thebacksheet 23 may be secured to the absorbent core 25 by a uniformcontinuous layer of adhesive, a patterned layer of adhesive, or an arrayof separate lines, spirals, or spots of adhesive. Adhesives which havebeen found to be satisfactory are manufactured by H. B. Fuller Companyof St. Paul, Minn. and marketed as HL-1258. The attachment means willpreferably comprise an open pattern network of filaments of adhesive asis disclosed in U.S. Pat. No. 4,573,986 entitled "DisposableWaste-Containment Garment", which issued to Minetola et al. on Mar. 4,1986, more preferably several lines of adhesive filaments swirled into aspiral pattern such as is illustrated by the apparatus and methods shownin U.S. Pat. No. 3,911,173 issued to Sprague, Jr. on Oct. 7, 1975; U.S.Pat. No. 4,785,996 issued to Ziecker, et al. on Nov. 22, 1978; and U.S.Pat. No. 4,842,666 issued to Werenicz on Jun. 27, 1989. Each of thesepatents are incorporated herein by reference. Alternatively, theattachment means may comprise heat bonds, pressure bonds, ultrasonicbonds, dynamic mechanical bonds, or any other suitable attachment meansor combinations of these attachment means as are known in the art.

The backsheet 23 is impervious to liquids (e.g., urine) and ispreferably manufactured from a thin plastic film, although otherflexible liquid impervious materials may also be used. As used herein,the term "flexible" refers to materials which are compliant and willreadily conform to the general shape and contours of the human body. Thebacksheet 23 prevents the exudates absorbed and contained in theabsorbent core 25 from wetting articles which contact the absorbentarticles, such as bedsheets and undergarments. The backsheet 23 may thuscomprise a woven or nonwoven material, polymeric films such asthermoplastic films of polyethylene or polypropylene, or compositematerials such as a film-coated nonwoven material. Preferably, thebacksheet is a thermoplastic film having a thickness of from about 0.012mm (0.5 mil) to about 0.051 mm (2.0 mils). Particularly preferredmaterials for the backsheet include RR8220 blown films and RR5475 castfilms as manufactured by Tredegar Industries, Inc. of Terre Haute, Ind.The backsheet 23 is preferably embossed and/or matte finished to providea more clothlike appearance. Further, the backsheet 23 may permit vaporsto escape from the absorbent core 25 (i.e., breathable) while stillpreventing exudates from passing through the backsheet 23.

The topsheet 21 is positioned adjacent the body surface of the absorbentcore 25 and is preferably joined thereto and to the backsheet 23 byattachment means (not shown) such as those well known in the art.Suitable attachment means are described with respect to joining thebacksheet 23 to the absorbent core 25. As used herein, the term "joined"encompasses configurations whereby an element is directly secured to theother element by affixing the element directly to the other element, andconfigurations whereby the element is indirectly secured to the otherelement by affixing the element to intermediate member(s) which in turnare affixed to the other element. In a preferred embodiment of thepresent invention, the topsheet 21 and the backsheet 23 are joineddirectly to each other in the blank's periphery and are indirectlyjoined together by directly joining them to the absorbent core 25 by theattachment means (not shown).

The topsheet 21 is compliant, soft feeling, and non-irritating to thewearer's skin. Further, the topsheet 21 is liquid pervious permittingliquids (e.g., urine) to readily penetrate through its thickness. Asuitable topsheet may be manufactured from a wide range of materials,such as porous foams; reticulated foams; apertured plastic films; orwoven or nonwoven webs of natural fibers (e.g., wood or cotton fibers),synthetic fibers (e.g., polyester or polypropylene fibers), or acombination of natural and synthetic fibers. Preferably, the topsheet 21is made of a hydrophobic material to isolate the wearer's skin fromliquids contained in the absorbent core 25. There are a number ofmanufacturing techniques which may be used to manufacture the topsheet21. For example, the topsheet 21 may be a nonwoven web of fibersspunbonded, carded, wet-laid, meltblown, hydroentangled, combinations ofthe above, or the like. A preferred topsheet is carded and thermallybonded by means well known to those skilled in the fabrics art. Apreferred topsheet comprises a web of staple length polypropylene fiberssuch as is manufactured by Veratec, Inc., a Division of InternationalPaper Company, of Walpole, Mass. under the designation P-8.

The disposable absorbent article preferably further compriseselasticized leg cuffs 36,38; 136,138 for providing improved containmentof liquids and other body exudates. Each elasticized leg cuff maycomprise several different embodiments for reducing the leakage of bodyexudates in the leg regions. (The leg cuff can be and is sometimes alsoreferred to as leg bands, side flaps, barrier cuffs, or elastic cuffs.)U.S. Pat. No. 3,860,003 describes a disposable diaper which provides acontractible leg opening having a side flap and one or more elasticmembers to provide an elasticized leg cuff (gasketing cuff). U.S. Pat.No. 4,909,803 entitled "Disposable Absorbent Article Having ElasticizedFlaps" issued to Aziz et al. on Mar. 20, 1990, describes a disposablediaper having "stand-up" elasticized flaps (barrier cuffs) to improvethe containment of the leg regions. U.S. Pat. No. 4,695,278 entitled"Absorbent Article Having Dual Cuffs" issued to Lawson on Sep. 22, 1987,describes a disposable diaper having dual cuffs including a gasketingcuff and a barrier cuff. While each elasticized leg cuff 32 may beconfigured so as to be similar to any of the leg bands, side flaps,barrier cuffs, or elastic cuffs described above.

The disposable absorbent article preferably further comprises an elasticwaist feature 35,37 that provides improved fit and containment. Theelastic waist feature is that portion or zone of the absorbent articlewhich is intended to elastically expand and contract to dynamically fitthe wearer's waist. The elastic waist feature at least extendslongitudinally outwardly from at least one of the waist edges of theabsorbent core 25 and generally forms at least a portion of the end edgeof the blank 17. Disposable absorbent articles are generally constructedso as to have two elastic waist features 35,37, one positioned in thefirst waist region and one positioned in the second waist region,although diapers can be constructed with a single elastic waist feature.Further, while the elastic waist feature or any of its constituentelements can comprise a separate element affixed to the absorbentarticle, the elastic waist feature is preferably constructed as anextension of other elements of the diaper such as the backsheet 23 orthe topsheet 21, preferably both the backsheet 23 and the topsheet 21.

The at least one elastic waistband 35,37 may be constructed in a numberof different configurations including those described in U.S. Pat. No.4,515,595 issued to Kievit et al. on May 7, 1985 and the abovereferenced U.S. Pat. No. 5,151,092; each of these references beingincorporated herein by reference.

FIG. 24 shows a top plan view of the web 58, wherein the blanks 17 areoriented with their longitudinal sides in the direction of transport, T,of the web 58. Leg cut-out regions 155 are provided along thelongitudinal sides 28,30 of the web 58 and waist elastic elements 35,37are applied transversely across the web.

In the embodiment of FIG. 25, the blanks 17 are oriented transverselywith respect to the web 58, such that the longitudinal sides of thepre-forms 17 correspond to the transverse sides of the web 58. The waistelastic elements 35,37 are applied along and substantially parallel tothe longitudinal sides of the web 58 such that they are maintained in anextended state at least during transport of the pre-forms and during thesealing step, the leg cut-out sections 156 extending through a centralpart of the web 58. In this embodiment, the pre-forms 17 may be rotatedby 90°, either prior to, or after gripping by the gripping means 60-63,to align the pre-forms 17 with the direction of transport T.

FIG. 26 shows a schematic top view of the position of the sealing areas43,49 of the blank 17 upon formation of a butt-type side seam. Thesealing means 153,154 compress the sealing areas 43,49 in the directionof the arrows C.

In the embodiment of FIG. 27, a side seam is formed which is acombination of a butt-type seam as shown in FIG. 2 and an overlappingseam as shown in FIG. 1. The seams of FIG. 27 can be obtained by firstplacing the sealing areas 43,49 in an abutting relationship as shown inFIG. 26, and by subsequently doubling-over of the abutting sealingareas. The doubled-over abutting sealing areas 43,49 are subsequentlycompressed between the sealing means 79 and the anvil carrier 69. Theseam formed in this manner is particularly strong as three layers ofmaterial are comprised in the seam.

FIG. 28 shows an overlapping seam in which three layers of material arecomprised. In this embodiment, the sealing area 43 is doubled-overbefore placing it in a superimposed relationship with the sealing area49. The doubled-over sealing area 43 may be obtained by doubling overone of the longitudinal edges 28,30 of the web 50 before cutting of theindividual blanks 17 and adhesively, or by heat-, or ultrasonic sealing,maintain the longitudinal edge in a doubled-over configuration.

What is claimed is:
 1. Method of making an undergarment (1) having sideseams (7, 9, 16, 18) from a substantially two-dimensional web (58), theweb having two longitudinal sides (28, 30) and a first transverse edge(24, 31) extending transversely to the longitudinal sides, the methodcomprising the steps of:transporting the web (58) in a substantiallyflattened position on a transport means (73, 105, 107, 112) along atransport trajectory, cutting the web (58) along a second transverseedge (26, 33) to form a two-dimensional pre-form (17), the pre-form (17)comprising the first and the second transverse edge (24, 31; 26, 33) andtwo longitudinal edges (27, 29), each longitudinal edge having two waistsections (39, 39'; 41, 41') and a crotch section (40, 40') locatedintermediate the waist sections, a sealing area (43, 45; 47, 49) beinglocated adjacent and inboard of each waist section, and wherein thelongitudinal edges of the pre-form (17) are formed by the transverseedges (24, 31; 26, 33) of the web (58), the transverse edges of thepre-form (17) corresponding to sections of the longitudinal sides (28,30) of the web (58), gripping the pre-form adjacent each waist sectionwith gripping means (60, 61, 62, 63) in four gripping areas (51, 53, 55,57), each gripping area being located near a respective sealing area,jointly rotating at least the gripping means which hold the grippingareas in the region of one of the transverse edges around at least onehinging axis (75, 77) extending substantially parallel to the transverseedges (24, 31; 26, 33) of the pre-form (17) to place the transverse edge(24, 31) generally parallel and opposite to the second transverse edge(26, 33), superimposing the sealing areas (43, 49; 45, 47) in acontacting relationship, joining the superimposed sealing areas in asealing means (78, 79), thus forming the undergarment, and releasing theundergarment from the gripping means.
 2. Method according to claim 1,wherein the step of superimposing the sealing areas comprises rotatingeach gripping means (60, 61, 62, 63) around a respective axis ofrotation (56, 56', 68', 68') extending generally parallel to thelongitudinal sides (27, 29) of the pre-form to place the sealing areasin an overlapping relationship to form overlapping side seams (7, 9), orin an abutting relationship to form abutting side seams.
 3. Methodaccording to claim 1, comprising the step of forming the web (58) bycombining a liquid-impervious backsheet (23, 23'), an absorbent core(25) and a liquid-pervious topsheet (21), such that the undergarment (1)is an absorbent article.
 4. Method according to claim 1, wherein aftergripping the pre-form (17) in the four gripping areas (51-57), at leastone said hinging axis (75, 77) is displaced to prevent stretching thepre-form (17) in the direction of the longitudinal edges (27, 29). 5.Method according to claim 1, wherein after gripping the pre-form (17) inthe four gripping areas (51-57), the distance between the gripping areas(51, 53; 55, 57) located along the same transverse edge is decreased toprevent stretching of the pre-form in the direction of the transverseedges (24, 31; 26, 33).
 6. Method according to claim 1, wherein thepre-form (17) is rotated towards a stationary sealing means (78, 79)around a main axis (80), which extends generally parallel to said atleast one hinging axis (75, 77) of rotation.
 7. Method according toclaim 6, wherein the gripping means (60,61, 62,63) are rotatedtangentially to the transport trajectory.
 8. Method according to claim7, wherein the circumferential velocity of the gripping means (60-63)around the main axis (80) is substantially equal to the speed oftransport of the web (58) along the transport trajectory.
 9. Methodaccording to claim 1, wherein the gripping means (60-63) comprisesuction means.
 10. Method according to claim 1, wherein the sealingmeans (78, 79) is an ultrasonic sealing unit.
 11. Method according toclaim 1, wherein multiple gripping means (60-63, 121-122) are mountedaround the main axis (80).
 12. Method according to claim 1, wherein thepre-form (17) comprises at least one elastic waist element (35, 37)extending substantially parallel to a transverse edge (24, 31; 26, 33),wherein the method comprises maintaining the at least one said elasticwaist element in an extended state at least during transport of thepre-form and during the sealing step.
 13. Method according to claim 12wherein the pre-form (17) comprises at least one said elastic waistelement (35, 37) along each transverse edge (24, 31; 26, 33).
 14. Anapparatus for making an undergarment (1) having side seams (7, 9, 16,18) from a substantially two-dimensional web (58), the web laving twolongitudinal sides (28, 30) and a first transverse edge (24, 31)extending transversely to the longitudinal sides, the web beingtransported along a transport trajectory and cut along a secondtransverse edge (26, 33) to form a two-dimensional pre-form (17), thepre-form comprising the first and second transverse edge (24, 31; 26,33) and two longitudinal edges (27, 29), each longitudinal edge havingtwo waist sections (39, 39'; 41, 41') and a crotch section (40, 40')located intermediate the waist sections, a sealing area (43, 45; 47, 49)being located adjacent and inboard of each waist section, the apparatuscomprising at least one folding-and-sealing unit (59), eachfolding-and-sealing unit (59) having a frame (72) and comprising:a) atleast a first and second carrier arm (64, 65, 66, 67), each carrier armbeing connected to the frame (72) and mounted on a hinging axis (75, 77)extending generally transversely to the carrier arms and substantiallyparallel to the transverse edges (24, 31; 26, 33) of the pre-form (17),b) gripping means (60, 61, 62, 63) attached to each carrier arm forgripping the pre-form (17) in four gripping areas (51, 53, 55, 57), eachgripping area being located near a respective sealing area, c) carrierarm-actuating means (70, 74, 84, 86, 88) for rotating at least thecarrier arm with the gripping means holding the gripping areas in theregion of one of the transverse edges around its hinging axis to asealing position, said carrier arm-actuating means having a lower member(84), and d) sealing means (78, 79) for contacting the pre-form in thesealing areas when the carrier arms and gripping means are in thesealing position.
 15. The apparatus according to claim 14, wherein thegripping means (60, 61, 62, 63) are rotatable around a respectivegripper axis (56, 56', 68, 68') which is positioned generally parallelto the carrier arms (64-67), the apparatus comprising gripper actuatingmeans (146, 148, 150, 152) for rotating each gripping means around thegripper axes to a sealing position.
 16. The apparatus according to claim14, the carrier arm-actuating means comprising:at least two connectingarms (86, 88) having a pair of hinge points, each said connecting armbeing rotatably attached to one of said carrier arms at one hinge point(89, 90) and attached to said lower member (84) of said carrierarm-actuating means at said other hinge point (91, 92), the carrierarm-actuating means being adapted to periodically vary the distancebetween the hinging axes (75, 77) and the hinge points (91, 92)attaching the connecting arms to the lower member.
 17. The apparatusaccording to claim 16, the hinging axes (75, 77) being located in theframe (72), the lower member (84) being displaceable relative to theframe (72) along a center line (95) located midway between the hingingaxes (75, 77) and extending generally transversely to the hinging axes.18. The apparatus according to claim 17, wherein each carrier arm(64-67) is connected with its hinging axes (75, 77) to a first end of arespective pivot member (93, 94), the second end of each pivot memberbeing rotatably connected to a central pivot axis (103) located on thecenter line (95) and extending generally parallel to the hinging axes(75, 77).
 19. The apparatus according to claim 18, wherein the apparatuscomprises two distance-control arms (96,98) each distance-control armbeing with one end hingingly connected to a respective connecting arm(86,88) and being with another end hingingly connected to a respectivehinge point (100,102) in the region of the center line (95).
 20. Theapparatus according to claim 18, comprising a sealing anvil (69) beingconnected to the lower member (84) on the center line (95), each saidcarrier arm (64-67) being in the sealing position located on each sideof the sealing anvil (69).
 21. The apparatus according to claim 14,wherein two gripping means (60-63) are connected to each carrier arm,the apparatus further comprising width-compensating means (128, 129,124, 125, 126, 127) for moving the gripping means (60-63) that arelocated on the same carrier arm in opposite directions generallyparallel to the hinging axes (75, 77).
 22. The apparatus according toclaim 14, wherein the folding-and-sealing unit (59) is rotatable arounda main axis (80) which is generally parallel to the hinging axes (75,77).
 23. The apparatus according to claim 22, wherein a plurality offolding-and-sealing units (59, 121, 122) is mounted at spaced apartangular positions around the main axis (80).
 24. The apparatus accordingto claim 22, wherein the carrier arms (64-67) are rotatable around themain axis (80) at the same circumferential velocity as the speed oftransport of the web (58).
 25. The apparatus according to claim 14wherein the frame (72) or the lower member (84) comprises a cam follower(85) that engages and rotates relative to a cam surface (120), forvarying the distance between the frame and the lower member.
 26. Theapparatus according to claim 14, wherein the gripping means (60-63)comprise vacuum gripper means.
 27. The apparatus according to claim 14,comprising an ejection member for radially discarding the undergarmentafter sealing of the sealing areas.